Many marine species can be identified using pictorial guides that highlight their main physical characteristics. However, there are also many marine species of lesser-known groups, such as sponges, that are hard to identify with photographs or illustrations due to their lack of complex morphological characters, and thus require specialized techniques.

Identifying spongesThe identification of sponges is very difficult due to their unique morphological traits and intraspecific variability in shape and colour. Therefore, proper identification often requires collection and microscopic examination of their skeleton.

Common features used to identify sponges are the following:

0 Spongin fibres – organic skeletal elements made of collagen and forming very complex networks in many sponges.

0 Dispersed collagen filaments – skeletal material found in all sponges

0 Spicules – inorganic elements present in almost all sponges’ skeleton and made of either calcium carbonate or silica.

The composition, geometry and arrangement of these components can be diagnostic at different

Identification of sponge speciesSpecies identification is important for ecological, evolutionary, systematic, and biodiversity studies, many of which contribute to the development of conservation and management plans.

taxonomic levels. For example, the classes of known sponges are separated based on these characteristics: the Calcarea have calcium carbonate spicules, the Hexactinellida, siliceous spicules and the Demospongiae, siliceous spicules and sponging fibres or both.

Still, many observable morphological characters can be used to aid in sponge identification including overall shape, distribution of surface pores, colour, texture and size. Knowledge of other non-morphological characteristics, such as the ecological traits of the different species can also be useful in sponge identification. Several tools, such as posters and field guides, and designed to be used by non-specialist individuals while at sea have been developed. A selection of these is provided in the FAO Vulnerable Marine Ecosystems webpage (www.fao.

org/in-action/vulnerable-marine-ecosystems/

background/vme-tools/en/). New tools, including the ones developed through SponGES will be incorporated in the FAO VME webpage.

SponGES has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 679849. This document reflects only the author’s view – the Executive Agency for Small and Medium-sized Enterprises is not responsible for any use that may be made of the information it contains.

info@deepseasponges.org deepseasponges.org @DeepSeaSponges @DeepSea_Sponges

A selection of sponge identification tools

AN EXAMPLE OF SPECIES IDENTIFICATION POSTERS FOR DEEP-SEA SPONGES OF

THE INDIAN OCEAN AND THE MEDITERRANEAN SEA

www.fao.org/3/a-i6324e.pdf

DEEP–SEA SPONGES OF THE INDIAN OCEAN

Hexactinellid glass sponges are unique amongst sponges in that they lack cell membranes and their silica spicules are based on a hexagonal (six-rayed) design. Spicules may be extremely large as in a 'fishing-rod', or may be twisted into 'rope', fused into a network, or form a soggy paper or rough sack-like fabric. Glass sponges are diverse in their shape: woven baskets and tubes, big sacks, fibreglass-like matting, soft tulips on stalks, and hollow and solid coral-like sticks. Texture may be stony, softly papery, brittle, fragile; always non-elastic. Coloration is muted, being translucent, white, cream, to faint pastel pinks and blues.

GLASS SPONGES – CLASS HEXACTINELLIDA

ACKNOWLEDGEMENTSThis poster was produced with the support of the FAO-

Norway Deep-Seas Fisheries Project (GCP/GLO/323/NOR).

It was prepared by Michelle Kelly and Di Tracey of NIWA,

New Zealand, under contract to FAO (Contract No.

2016/HQR/FIAFC-CPA 323044), with significant input

from Henry Reiswig (Royal British Columbia Museum),

Sadie Mills, Rob Stewart, and Erika Mackay of NIWA

(supply of specimen images). Images were also supplied

by Coral Reef Research Foundation, Republic of Palau and

Cara Fiore, Woods Hole Oceanographic Institution,

U.S.A. Images are copyright of NIWA, CRRF and C. Fiore.

The illustration of the general structure of a sponge was

provided by E. Zaikova and S. Hallam.

SIMILAR LOOKING GROUPSHexactinellids forming lacy networks look like perforated lace corals, but lace corals are composed of tiny visible box animals. Hexactinellids forming rigid, hollow ‘trees’ or solid ‘sticks’ look like gorgonian corals, but these are flexible and have polyps.

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Demospongiae come in an enormous variety of shapes and sizes, from thinly encrusting masses, hemispheres, spheres, tiny globes and lollipops, to large volcano-like forms several metres high. Others resemble flasks and tall tubes, or have fan and tree-like forms. Coloration is derived from carotenoid pigments (purple, magenta, blue, brown, red, pink, orange, ochre and yellow), or due to the presence of symbionts or specific metabolites. Texture reflects the underlying mineral (spicule) and organic (collagen, fibre) skeleton and may be fleshy, woody, stony or fibrous. Demosponge skeletons may include spicules, sand grains, collagen and fibre, in various combinations.

SILICEOUS SPONGES – CLASS DEMOSPONGIAE(PORIFERA) PHYLUM

SPONGES

Sponges are common invertebrates in the deep sea, providing habitat for certain benthic fauna. They attach to hard substrate on seamounts, hydrothermal vents, pinnacles and canyons, hard corals, or anchor in sediment. Sponges feed by filtering sea-water to capture food particles and oxygen, but an unusual group, the 'carnivorous sponges', feed directly on small crustaceans by entanglement and direct digestion. Water flows into a sponge through small openings (ostia) that occur over the outer surface and leave the sponge through one or more, larger, exhalent openings (oscules).

Sponges do not have discrete 'tissues'; different cell types perform the functions of digestion, excretion, reproduction and defence. A skeleton of mineral silica or calcium carbonate spicules and organic collagen provides support for these cells. The form, dimensions and arrangement of the spicules can help with their identification. Sponge chemicals are known for their potential application to human health and industry.

Tiny ‘carnivorous’ demosponges resemble more robust sea fans; sea-fan octocorals have polyps. ‘Hard as rock’ demosponges look like stony corals, hydrocorals and lace corals (bryozoans), but these are tree-shaped and often glass smooth and the lace corals are composed of tiny visible box animals. Lollipop demosponges look like stalked sea squirts, but these form gelatinous ‘purses’ with two openings.

Size: up to 40 cm high~

Tulip-shaped sponges with a large, cup-shaped to elongate body on a stem of glass threads, resembling a twisted rope that roots the sponge into sediment. Glass rope often the only part collected. Texture of body soggy when wet, crisp and fibrous when dry; fragile, easily torn and detached. Colour in life tan to grey.

Depth: 198–4077 m

Hyalonema spp. Chalaronema sp. Dredged ‘glass rope’

Hyalonematidae species

Fishing rod-shaped sponge, comprising a single, massive spicule. A papery body clings to the upper portion of the spicule that roots the sponge into soft sediment. Texture of body soggy when wet, fibrous and fragile when dry; easily detached. Colour of body cream to pale green.

Depth: 1567–2550 m

Monorhaphis chuni

Size: 10 cm long (2 mm ) to 3 m long (1 cm ) Ø Ø

Monorhaphis chuniCladorhizidae species

Feather-, tree-, sunflower- or lollipop-shaped 'carnivorous' sponges, with 'sticky' filaments or balloon-shaped spheres on which living 'food' is caught. Attached by a 'root' in soft substrate or by a rounded disc to hard substrate. Texture soft, compressible or hard and twiggy, often fragile. Colour in life beige, pink.

Abyssocladia sp. Asbestopluma sp. Chondrocladia spp.

Massive, flattened spherical to bowl-shaped sponges, with a smooth, granular or roughened, hairy surface. Oscules usually grouped at apex. Texture usually tough, incompressible. Skeleton dominated by harsh spicules that radiate internally and project from the surface, often with a discrete 'rind.' Colour in life white, cream, tan, brown or grey.

Stelletta rugosa Stelletta sp.

Ancorinidae species

Size: several mm high to 30 cm high~ Depth: 60–2930 mDepth: 1–2800 m Size: ~ 10 to 40 cm Ø

Rossellidae sack sponges

Size: may reach 1 m Ø Depth: 100–2000 m

Hyalascus sp. Acanthascus sp. Rhabdocalyptus sp.

Large vase or floppy, sack-shaped sponges resembling mushy paper when wet. Often collected as bits of 'sacking'. Outer walls smooth or conulose; inner walls smooth with exhalent perforations. Attached to substrate by a basal plate or into soft sediment with a 'beard' of glass spicules. Texture soft like sacking or felt. Colour in life tan.

Pheronema annae and other Pheronematidae

Pheronema annae Pheronema sp.

Spherical to oval sponges with a large exhalent opening on the upper surface and a 'beard' or 'fringe' of glass spicules that roots the sponge into sediment. Surface smooth, covered in a distinctive, detachable network, with tufts of long spicules in some species. Internally cavernous. Texture tough, fibrous and slightly compressible. Colour in life tan.

Depth: 502–3480 mSize: up to 40 cm Ø

Massive, thin, flattened, single to multiple fans, with indented margins resembling a palm with fingers, to finger-forming sponges, with a generally smooth but microscopically roughened surface. Exhalent and inhalant openings on margins or opposite faces. Texture tough, flexible. Skeleton a dense fibrous network. Colour in life cream, tan, pale orange, deep orange.

Isodictya sp. Isodictya sp. Iophon sp.

Massive, thick, irregular, undulating plate or fan, attached along a broad base to hard substrate. Margins and surfaces extremely harsh with long, projecting spicules. Exhalent and inhalant openings not visible. Texture tough, flexible. Skeleton a harsh, dense siliceous network. Colour in life white with grey overlay on margins from sediment trapped by spicules.

Poecillastra schulzei P. schulzei

Fibrous fan spongesPoecillastra schulzei (fibreglass fan sponge)

Size: up to 40 cm Ø~ Depth: 3–1652 mDepth: 696–2040 m Size: up to ~ 30 cm Ø

Massive, spherical, turban- to cheese-shaped sponges, with a smooth or lobed, granular or hairy surface. Several oscules on the apex separated from grouped ostia. Texture tough, eggshell-like, incompressible; softer inside, often pulling away from shell-like 'rind'. Skeleton dominated by hard eggshell-like rind, spicules radiate internally. Colour cream, beige, tan, brown or grey.

Depth: 1–2260 m Size: ~ 5 to 30 cm Ø

Geodia sp. Geodia sp.

Geodiidae species

Rigid honeycomb sponges in vase, bush, or feathery, tree-like shapes, with a distinctive tubular or flaring morphology, walls a regular or irregular perforated 'netting' with larger perforations in some groups. Surface smooth, undulating or ridged. Attached to hard substrate by a basal plate. Texture brittle, delicate, pumice-like when dry. Colour in life white, cream.

Honeycomb lace sponges (Hexactinosida, Aulocalycoida)

Vase-shaped sponges with a distinctive colander-like sieve-plate over the apex. Walls resemble basket-weave. Attached to hard substrate by a hard basal plate or into soft sediment with a 'beard' of glass spicules. Surface softly ridged around perforations or forms a beautiful tangential network. Texture floppy and fabric soft or stony crystalline. Colour in life tan.

Euplectellidae species

Size: 2 to 60 cm long

Auloplax sp.

Depth: 10–3875 m

Aphrocallistes beatrix

Depth: 172–4744 mSize: up to 40 cm~

Euplectella spp. Regadrella spp.

Massive 'hard as rock' sponges forming wavy plates, cups, tubes or ears. Oscules and ostia often separated on opposite sides of the wall, or in a concave recess (Callipelta). Attached by a narrow base or margin to hard substrate. Margins and upper surface often hairy. Texture stony. Skeleton a rigid mass of interlocked spicules. Colour cream, tan.

Microscleroderma herdmaniLeidermatium intermedia Corallistes sp.

Spaceship-shaped sponges with a distinctive rounded summit, separated from the base by a narrow transverse mid-section recess, providing a specialised inhalant area. Oscules may be visible on upper surface. Rooting structures project from the ventral surface. Surface fleshy, rough. Texture soft, compressible. Skeleton with harsh, long, radiating spicules. Colour beige to grey.

Thenea sp.

'Hard as rock' sponge cupsThenea species

Depth: 3–375 m Size: 2 to 40 cm ØDepth: 238–1153 m Size: ~ 1 to 7 cm Ø

Size: up to 70 cm high~

Bubbly cup-shaped sponge with a long, slender, hollow, thin-walled stem, attached to hard substrate by a disc. Concave apex has large perforations, external surface has udder-like structures. Texture of body very soft, flimsy, collapses out of water. Crisp and fragile when dry, stem easily broken and body torn or detached. Colour in life white.

Depth: 890–2760 m

Saccocalyx pedunculatus

Saccocalyx pedunculatus

Caulophacus spp. Crateromorpha sp.

Tulip, mushroom, or chalice-shaped sponges with a large, open, cup-shaped body on a stiff, coral-like or soft, flexible, tubular stem. 'Glass sponge sticks' often the only part collected. Texture of stem stony to fibrous, slightly compressible, body soggy when wet, crisp and fibrous when dry; fragile, easily detached. Colour in life tan to pink.

Depth: 240–4714 mSize: up to 40 cm high~

Rossellidae chalice sponges

Hockey-stick shaped to branching sponges with a tough, internal, tree-like core from which emerges a soft, fuzzy or tough, leathery swelling along the upper branches. Oscules are prominent on the swollen sections and/or restricted to one side only. Attached to substrate by a tough, branching 'root'. Colour in life cream to pale yellow.

Lollipop-shaped sponges with a large, bullet-shaped to oval head and a slender stem. Attached in soft sediment by a branching 'root' and to hard substrate by a rounded disc. Texture of head softer than stem, smooth or furry; stem, smooth, tough, incompressible and flexible. Colour in life grey, cream, dull yellow.

Homaxinella species Lollipop sponges

Living Homaxinella sp.

Depth: 13–2675 m Size: 30 to 60 cm long Depth: 30–975 mSize: <10 cm (Podospongia), up to 30 cm high (Stylocordyla)

Gorgonian octocorals (sea-fans)

Similar looking groups to Class Demospongiae

Ascidians (sea squirts) Bryozoan (lace coral) Ascidians (sea squirts)Stony coral Stylasterid hydrocorals

Similar looking groups to Class Hexactinellida

Ecionemia sp. Stelletta lithodes

Homaxinella balfourensis Homaxinella sp.

Poecillastra sp.

Podospongia sp. Stylocordyla borealis

Farrea spp.

Bryozoan (lace coral)

DEEP-SEA SPONGES OF THE MEDITERRANEAN SEASILICEOUS SPONGES – CLASS DEMOSPONGIAE

Demosponges, also known as siliceous sponges, represent the largest and most diverse class within Porifera, comprising 85%, more than 6 600, of all sponge species. Their shape and size range from thin crusts, to various sizes of globular, vase-, cushion-, tree-like and giant barrels more than 2 m high. Coloration, derived from pigments or symbiotic associates, covers a wide spectrum (from white to black) including yellow, orange, red, blue, green, purple, brown, etc. Consistency depends on the skeletal composition and varies between soft, compressible, elastic, to tough and rock hard. The surface texture varies from smooth, velvety to rugose, and hispid. Approximately 670 demosponge species are known to occur in the Mediterranean Sea.

SPONGES (PHYLUM PORIFERA)Sponges are amongst the most ancient animals to have appeared in the world’s oceans. Currently, more than 8 000 species are recognized but over 25 000 are estimated to exist. They are distributed at all depths and latitudes, and in some areas form highly structured habitats known as sponge grounds, aggregations, gardens or reefs, particularly so in the deep-sea. These habitats play key ecological roles such as: serving as shelter and nursery, and providing food for numerous other species of invertebrates and fish; mediating the transfer of energy between the benthic and pelagic systems; and participating in biogeochemical cycling processes. Unlike most other animals, sponges lack true tissues or organs. Instead, they have specialized cells carrying out specific functions and a body arranged around a canal system that filters water for food and oxygen.

The only exception are the carnivorous sponges (family Cladorhizidae) that feed directly on small crustaceans. The sponge skeleton is made up of mineral (siliceous or calcareous spicules) and/or organic (spongin, collagen) elements, although a few species lack a skeleton altogether. The surface of the sponge holds numerous inhalant and exhalant pores, known as ostia and oscules, through which the water enters and exits the sponge. Species identification is primarily based on the analyses of the skeleton, alongside with external characteristics. Sponges are divided into four classes, of which two, the Demospongiae and Hexactinellida, are the most common and important in the deep-sea.

GLASS SPONGES – CLASS HEXACTINELLIDA Hexactinellids, also known as glass sponges, constitute a predominantly deep-sea group, typically occurring at bathyal and abyssal depths (i.e. below 200 m). They are exclusively marine and comprise approximately 675 species worldwide, of which nine occur in the Mediterranean Sea. Their external morphology usually varies between vase, blade, cup or tube-shaped and both stalked and non-stalked forms exist. They attach to hard bottom using a basal disc or anchoring spicules, or to soft sediment by means of root-like structures. Coloration is mostly in shades of white, beige and yellow.

Globular sponges with rooting structures (Thenea muricata)Globular to egg-shaped sponges with one or few apical oscules. They are characterized by a distinct groove around the mid-section of the body, where inhalant pores (ostia) are located, and root-like structures projecting from the base, by means of which they attach to soft substrate. Consistency is slightly compressible and texture is smooth. Colour is white to brownish/greyish.

Size: up to 5-6 cm in height/diameter Depth and substrate: 300–2 000 m; sand or mud

Thenea muricata

Fan-shaped, white and orange sponges (Pachastrella, Poecillastra)Laterally flat, massive sponges with a hard but friable consistency and a rather thick appearance. Surface more or less smooth with flat, visible oscules. Pachastrella monilifera is light coloured, whitish, more hispid and often partially covered by sediment. Poecillastra compressa is usually bright orange, although whitish specimens are known. It has larger oscules concentrated on one of the two sides. Occasionally cup-shaped.

Size: up to 20 cm wide Depth and substrate: 50–800 m; rock, coral rubble

Pachastrella monilifera Poecillastra compressa

Massive, volcano-like sponges (Haliclona magna)A massive, whitish sponge with large tubular or conical processes at times covered by sediment or by a cyanobacteria film giving it a purple-brownish coloration. Processes often with one or few major oscules reaching a large diameter. The rim of the oscules is thinner and somehow transparent. Texture is smooth and consistency is soft turning brittle when dried.

Size: up to 40 cm in height Depth and substrate: 130–300 m; rock

Haliclona magna

Arborescent yellowish sponges (Antho dichotoma)Stalked arborescent sponge, dichotomously branched (i.e. each branch splits into two). The branches are flexible, much more so than the stalk. Oscules are not clearly visible. Consistency is firm and texture is finely hispid. Coloration is yellowish to light brown.

Size: up to 30 cm in height Depth and substrate: 0–800 m; rocky bottom

Antho dichotoma

Lollipop spongesLollipop-shaped sponges with a large, circular (Stylocordyla pellita) to oval and apically compressed (Rhizaxinella pyrifera) “head” and a slender stalk. One oscule is visible at the top of the head. S. pellita, grey or cream in colour, has a smooth and flexible stalk, and is attached to hard substrates by means of a rounded disc while R. pyrifera, dull yellow, has an occasionally knobbed or branched rigid stalk, and lives in soft sediment thanks to a branching root-like structure.

Size: less than 15 cm in height Depth and substrate: 250–800 m; sand or rock

Stylocordyla pellita Rhizaxinella pyrifera

Globular sponges with apical oscula (Suberites spp.)Globular sponges with usually one large apical oscule. Some species (e.g. S. ficus) have a short and thick peduncle. Consistency is firm yet slightly compressible. The surface is even and velvety. Colour varying from yellow to orange, red and brown. S. domuncula frequently associated to hermit crabs shell.

Size: up to 10 cm in diameter Depth and substrate: 0–800 m; mixed; S. domuncula frequently associated to hermit crabs shell

Suberites domuncula S. ficus Suberites sp.

Light coloured conulose sponges (Dysidea spp.)Cushion-shaped, somewhat lobose, sponges. Oscules, variable in size (depending on the species), are usually scattered around the sponge. The surface is “spiky” (conulose) due to the lifting of the surface layer by spongin fibres. Consistency is elastic. Coloration whitish to yellowish but some species have a pink, violet or bluish tinge. The spikes are usually lighter in colour than the rest of the sponge.

Size: up to 20–30 cm across Depth and substrate: 0–300 m; rocky bottom

Dysidea avara Dysidea sp.

Lamellate rock sponges (Leiodermatium pfeifferae)Erect sponges with a lamellate shape, from irregular to convoluted masses. The convex (inhalant) side of the plate has many small evenly-distributed ostia, whereas the concave (exhalant) side has fewer larger elevated oscules. Consistency is rock-hard and texture is rough. Colour is off-white to light brown sometimes presenting a light blue tinge.

Size: up to 1 m across Depth and substrate: 300–2 000 m; mixed or rock

Leiodermatium pfeifferae

Massive, hard sponges (Geodia spp.)

Massive sponges coming in a variety of shapes, from irregular to convoluted masses; younger specimens are usually (sub)spherical. Oscules are grouped together and located in depression areas located on the top surface of the sponge. Small inhalant pores (ostia) are also grouped together but found distributed across the overall surface. G. barretti, cream in colour, has an even and clean surface with a rubbery texture. G. cydonium, yellow in colour, has a hispid/harsh surface often covered with sediment. Both species have a tough but slightly compressible consistency.

Size: up to 50 cm in diameter Depth and substrate: 300–2 000 m; mixed or rock

Geodia barretti Geodia cydonium

Stalked, fan-shaped sponges (Phakellia spp.)Thin, cup- or fan-shaped sponges attached to the substrate by a fairly narrow stalk, with a smooth surface and small oscules on one side. Specimens of Phakellia ventilabrum are whitish beige and have thin and frayed edges with a characteristic pattern of vein-like lines fanning out. Phakellia robusta is rather similar but has a more ochre-yellow coloration, a thicker blade and more textured surface. They are both quite flexible.

Size: up to 30 cm in height/width Depth and substrate: 200–800 m; rock, gravel beds

Phakellia ventilabrum Phakellia robusta

Mediterranean stony sponge (Petrosia ficiformis)Massive lobose sponges with large sharp-edged oscules on the upper side. Consistency is hard but slightly compressible, crumbly inside. Texture is velvety. Outer coloration varies from dark red/burgundy (in shallower areas) to off-white (in deeper and darker areas) whereas inner coloration is always off-white.

Size: up to 50 cm across Depth and substrate: 0–800 m; rocky bottom.

Petrosia ficiformis (burgundy morph)

Petrosia ficiformis (white morph)

Massive, tubular gold sponges (Aplysina spp.)Massive sponges with a cushion-like base from which several finger-like tubes project. The tubes are somewhat flattened at the top and bear a single large oscule. Consistency is somewhat flexible and compressible. Texture is rubbery and slightly rugose. Colour is golden yellow when fresh, turning to greenish-blue black after a few minutes of exposure to air.

Size: up to 25 cm in height Depth and substrate: 0–300 m; rocky bottom.

Aplysina aerophoba (freshly collected)

Aplysina aerophoba (upon air exposure)

Pine-tree sponge (Cladorhiza abyssicola)Erect sponge resembling a pine-tree, with a central axis from which several branches depart. Each branch may have secondary branches. Both the axis and branches carry thin filaments projected in all directions. It attaches to the substrate by means of root-like structures. Consistency is firm, the branches are stiff and the texture is a bit harsh. White in colour.

Size: up to 20 cm in height

Depth and substrate: 300–2 000 m; soft bottom.

Cladorhiza abyssicola

Birds’ nest sponge (Pheronema carpenteri)Globular to sub-cylindrical sponges possessing a wide and deep atrial cavity with a large apical oscule. The surface is “hairy” and shows an intricate network of spicules. Texture is fibrous and compressible. It is attached to the substrate by means of a basal tuft of spicules. Can be found in large numbers as the only species or alongside other sponge species, i.e. it forms sponge aggregations.

Size: up to 20 cm in height Depth and substrate: 300–2 000 m; on soft or mixed substrate

Pheronema carpenteri

Felt vase sponge (Asconema setubalense)Vase sponge with a thin fibreglass-like wall, folding outwards at the top. Colour is off-white to grey or brownish with sediment. When collected by dredge/trawl, the appearance can be that of “felt” shreds. Can be found in large numbers, i.e. it forms sponge aggregations.

Size: up to 1 m in height Depth and substrate: 300–2 000 m; on soft or mixed substrate

Asconema setubalense

White bouquet sponge (Farrea bowerbanki)Thin-walled reticulated tubes branching outwards from a basal attachment point to form a globular “bouquet”. The tubes are open and increasingly wider and wavy at their extremity. Consistency is hard but fragile and texture is like fine sand paper. Coloration is crisp white.

Size: up to 30 cm diameter Depth and substrate: 300–2 000 m; on rocky substrate

Farrea bowerbanki

White funnel with finger-like projections (Aphrocallistes beatrix)Funnel-shaped sponge with lateral finger-like projections often directed towards the base. The top of the sponge is covered with a rigid network-like plate. The surface has a very characteristic regular hexagonal honeycomb appearance. Consistency is hard but fragile and texture is like rough sand paper. Live coloration is bright white, whereas dead tissue appears brown.

Size: up to 20 cm in height Depth and substrate: 300–2 000 m; on hard substrate, often over corals or other sponge skeletons

Aphrocallistes beatrix (top view)

Aphrocallistes beatrix (lateral view)

SIMILAR LOOKING GROUPS (ALGAE, ANTHOZOANS, BRYOZOANS, ASCIDIANS) Branched, arborescent and flexible sponges can be easily misidentified as gorgonian corals, but a close look will evidence the lack of polyps (one of the principal body form occurring in the group of corals and represented by a column with a crown of tentacles). Rock sponges are similar to scleractinian corals, whereas glass sponges with a rigid, reticulated and white skeleton can be mistaken for hard corals and bryozoans. Globular, rigid sponges can be misidentified as contracted solitary or colonial ascidians especially when oscules are still evident. Rigid sponges with a high density of spicules and cyanobacterial coverage can be mistaken for coralline algae.

ACKNOWLEDGEMENTS The authors of this poster are Joana Xavier (Biology Department and K. G. Jebsen Centre for Deep-Sea Research, University of Bergen, Noeway) and Marzia Bo (Dipartimento per lo Studio del Territorio, dell’Ambiente e della Vita, University of Genoa, Italy). Numerous scientists are to be acknowledged for their helpful comments and for image supply: Caterina Longo and Frine Cardone (University of Bari), Maurizio Pansini and Marco Bertolino (University of Genoa), Manuel Maldonado (CSIC Blanes), Jordi Grinyó, Carlos Dominguez, and Andreu Santín (CSIC Barcelona), Francisca Carvalho and Jon Hestetun (University of Bergen), Claudio Lo Iacono (National Oceanography Centre Southampton), Jean Vacelet, Nicole Boury-Esnault, and Maïa Fourt (IMBE and Aix-Marseille Université), Paco Cárdenas (University of Uppsala), Vasilis Gerovasileiou (HCMR Athens), Eleni Voultsiadou (AUTH Thessaloniki), Javier Cristobo and Pilar Rios (IEO Gijón).

Gorgonian Gorgonian Coralline algae Coralline algae Ascidian Bryozoan

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The FAO VME DataBase (http//www.fao.org/in-action/vulnerable-marine-ecosystems/background/

vme-tools/en/) contains some of the existing tools developed for the identification and protection

of vulnerable marine ecosystems (VMEs) – including for sponges.

CORAL, SPONGE, AND

OTHER VME INDICATOR

IDENTIFICATION GUIDES

FOR THE NORTHWEST

ATLANTIC AREA

archive.nafo.int/open/studies/s47/s47.pdf

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All photos courtesy of DFO, Canada